def __init__(self, grammar, trace=0, **property_names):
        """
        Create a new C{BottomUpPCFGChartParser}, that uses C{grammar}
        to parse texts.

        @type grammar: C{PCFG}
        @param grammar: The grammar used to parse texts.
        @type trace: C{int}
        @param trace: The level of tracing that should be used when
            parsing a text.  C{0} will generate no tracing output;
            and higher numbers will produce more verbose tracing
            output.
        """
        assert _chktype(1, grammar, PCFG)
        assert _chktype(2, trace, types.IntType)
        self._grammar = grammar
        self._trace = trace
        AbstractParser.__init__(self, **property_names)
    def __init__(self, grammar, trace=0, guessUnknown=0, spellchecker=None, **property_names):
        """
        Create a new C{ViterbiPCFGParser}, that uses {grammar} to
        parse texts.

        @type grammar: C{PCFG}
        @param grammar: The grammar used to parse texts.
        @type trace: C{int}
        @param trace: The level of tracing that should be used when
            parsing a text.  C{0} will generate no tracing output;
            and higher numbers will produce more verbose tracing
            output.
        """
        assert _chktype(1, grammar, PCFG)
        assert _chktype(2, trace, types.IntType)
        self._grammar = grammar
        self._trace = trace
        self._guessUnknown = guessUnknown
        self._guessKnown = 0
        self._spellchecker = spellchecker
        AbstractParser.__init__(self, **property_names)